1. Field of the Invention
The present invention relates to a disk drive apparatus and, more particularly, to a disk drive apparatus used with a sector servo system.
2. Description of the Prior Art
A sector servo system is one of the systems for controlling the movement of a disk-drive head on the basis of servo signals recorded on a disk-like recording medium and which are intermittently reproduced therefrom.
In a sector server system, servo signals which are intermittently obtained from servo signal recording regions formed radially on a magnetic disk at equal angle intervals are processed by a servo signal processing circuit for executing control operations such as a seeking operation of a magnetic head, tracking operation, and the like.
Hitherto, an analog circuit such as an operational amplifier or the like has been used as the above servo signal processing circuit.
In recent years, however, an advanced control technique has become required due to a higher density and a larger capacity of the recording media. To realize such an advanced control technique, high speed digital arithmetic operating processing using a DSP (Digital Signal Processor) is needed.
The DSP executes arithmetic operating processing at a high speed. With respect to a point on a gate scale, that is, a fraction of the gates which the DSP occupies in the whole circuit in the disk drive apparatus, for instance, the hard disk drive apparatus, is large, so that there is generally a problem in that the electric power consumption is large.
That is, the large electric power consumption of the DSP results in a large electric power consumption of the hard disk drive apparatus.
As a future trend, it is considered that small hard disk drive apparatus will be further widely used in portable personal computers, word processors, or the like. For this purpose, the realization of a low electric power consumption of the servo signal processing circuit, practically speaking, the DSP, is demanded.